Land-Use Change and Water-Related Ecosystem-Service Trade-Offs in a Tropical Peat-Swamp Landscape: Coupled CA–Markov–InVEST Projections and an Economic Valuation

Land-use change alters carbon storage, water balance, and sediment dynamics in tropical peat swamps. This study projected land-use change in Kuan Kreng, Thailand, under business-as-usual (BAU) and agricultural expansion (AGRI) scenarios using CA–Markov and assessed ecosystem services and economic outcomes using InVEST. Sample-based backcasting yielded 92.72% overall accuracy (Kappa = 0.911); however, full-map accuracy (91.65%) was below the persistence benchmark (95.26%), and the Figure of Merit was 8.39%, indicating limited change-specific predictive performance. By 2046, AGRI produced greater agricultural expansion and swamp-forest loss than BAU. Relative to 2021, carbon storage declined by 2.83% under AGRI, while modeled annual water yield increased by 4.57% under BAU and 6.48% under AGRI. Sediment export increased by 22.62% and 35.76%, whereas avoided export increased by 12.99% and 22.45%, respectively, indicating greater sediment generation rather than improved regulation. The direction-adjusted Ecosystem Service Change Index reached −0.0911 under BAU and −0.1502 under AGRI. By 2046, AGRI had a USD 2.39 million lower carbon-stock value and a USD 0.47 million yr−1 higher potential water-supply value than BAU. The findings provide conditional comparisons of land-use-driven ecosystem-service responses, although uncertainties in spatial land-change allocation and peatland hydrological representation limit their interpretation as precise forecasts.